1. Field of the Invention
The present invention relates to a journal thermal printer apparatus.
2. Description of the Related Art
A thermal printer that uses a heat sensitive paper roll has a printer unit including a thermal head and a platen roller.
Such a thermal printer may be applied to a receipt printer that is configured to cut and output printed paper to be handed to a customer, or a journal printer that is configured to roll up the printed paper.
It is noted that the receipt printer is generally arranged to have a clam shell type printer configuration in order to facilitate setting of a heat sensitive paper roll. The clam shell type printer includes a roll accommodating portion, a cover that may be opened/closed through rotation to cover/uncover the roll accommodating portion, and a platen roller that is arranged at the edge of the cover. When the cover is closed, the platen roller holds the heat sensitive paper between the platen roller and the thermal head, and when the cover is raised and opened, the upper side of the roll accommodating portion is uncovered so that a heat sensitive paper roll may be easily set therein.
It is noted that the receipt printer may be embodied as a portable thermal printer that is configured to be carried by an operator. Accordingly, techniques are being developed for realizing miniaturization of the receipt type thermal printer.
The journal printer uses a heat sensitive roll that is large in diameter. It is noted that generally, a smaller number of lines are printed in one print job performed at the journal printer compared to that performed at the receipt printer. For example, in a POS (Point of Sale) terminal used at a retail store, information on each item of purchase made by a customer is printed at the receipt printer, whereas at the journal printer, the total price of the items purchased by a customer is printed so that only one line is used for each customer. Since the heat sensitive paper roll is less frequently exchanged and for other reasons, the journal printer is generally not arranged into the clam shell type printer configuration. Accordingly, in order to exchange the heat sensitive paper roll in the journal printer, a cover arranged at a side of the POS terminal has to be removed, and the heat sensitive paper roll has to be exchanged from the side of the POS terminal.
The journal printer has conventionally been used as a stationary printer, and thereby, the configuration described above has been adequate for serving its purpose.
However, from now on, with the growing diversification of services, application of the journal type thermal printer as a portable thermal printer may be in demand.
Thus, a technique is required for arranging the journal thermal printer into the clam shell type configuration, and miniaturizing the journal thermal printer.
It is noted that in the journal printer, an operation of rolling up printed paper has to be stably performed. Also, upon configuring the journal printer into a portable printer, measures need to be implemented to prevent malfunction of the journal printer from occurring regardless of the position in which the journal printer is held.
Japanese Laid-Open Patent Publication No. 11-185064 discloses a journal thermal printer that includes a top cover that may be opened/closed, and a platen roller that is attached to the top cover.
However, in the disclosed journal printer, the operation of rolling up printed paper is realized using friction generated at the heat sensitive roll when the heat sensitive paper is pulled, and in such an arrangement, the operation of rolling up the printed paper cannot be stably performed. Also, the printed side of the printed paper may rub against the heat sensitive paper being pulled out from the heat sensitive paper roll so that the heat sensitive paper pulled out from the heat sensitive paper roll may be unnecessarily tainted.